You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@jena.apache.org by "Andy Seaborne (JIRA)" <ji...@apache.org> on 2011/03/16 23:51:29 UTC
[jira] Commented: (JENA-41) Different policy for concurrency access
in TDB supporting a single writer and multiple readers
[ https://issues.apache.org/jira/browse/JENA-41?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13007718#comment-13007718 ]
Andy Seaborne commented on JENA-41:
-----------------------------------
See design note: https://cwiki.apache.org/confluence/display/JENA/TxTDB
> Different policy for concurrency access in TDB supporting a single writer and multiple readers
> ----------------------------------------------------------------------------------------------
>
> Key: JENA-41
> URL: https://issues.apache.org/jira/browse/JENA-41
> Project: Jena
> Issue Type: New Feature
> Components: Fuseki, TDB
> Reporter: Paolo Castagna
>
> As a follow up to a discussion about "Concurrent updates in TDB" [1] on the jena-users mailing list, I am creating this as a new feature request.
> Currently TDB requires developers to use a Multiple Reader or Single Writer (MRSW) locking policy for concurrency access [2]. Not doing this could cause data corruptions.
> The MRSW is indeed a MR xor SW (i.e. while a writer has a lock, no readers are allowed and, similarly, if a reader has a lock, no writes are possible).
> This works fine in most of the situation, but there might be problems in presence of long writes or long reads.
> It has been suggested that a "journaled file access" could be used to solve the issue regarding a long write blocking reads.
> [1] http://markmail.org/message/jnqm6pn32df4wgte
> [2] http://openjena.org/wiki/TDB/JavaAPI#Concurrency
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira